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Networking concepts and hardware

Networking concepts and hardware. Basic Communications Model Standards are needed at all Layers. User Layer. Application Layer. Computer (Transport) Layer. Transmission Layer. Subnet Layer. Station B. Station A. 2. 2. 1. 1. 4. 3. Transmission of Messages

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Networking concepts and hardware

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  1. Networking concepts and hardware

  2. Basic Communications ModelStandards are needed at all Layers User Layer Application Layer Computer (Transport) Layer Transmission Layer

  3. Subnet Layer Station B Station A 2 2 1 1 4 3 Transmission of Messages 1. Within a Single Subnet, or 2. in Point-to-Point Links Between Subnets

  4. Internet Layer Station B Station A 2 1 4 3 Routing of Messages Across multiple subnets in an internet

  5. Internetting Station B Station A 2 1 4 3 internet: collection of subnets such that any station on any subnet can communicate with any other station on any other subnet simply by giving the internet address of the other station.

  6. Layering in Major Architectures Basic Model TCP/IP IPX/SPX OSI Application Application Application Application (7) Presentation (6) Computer (Transport) Transport: TCP, etc. Complex: SPX, etc. Session (5) Transport (4) Internet Internet Internet Network (3): Internet & Subnet Subnet (OSI) Subnet (OSI) Subnet (OSI) Data Link (2) Physical (1)

  7. LANs, MANs, & WANs • LAN • Local area network • Single office, building, campus • 10 Mbps to 100 Mbps to the desktop common • 1 Gbps coming • Will carry most traffic, because most traffic is local

  8. PC Networking on a small LAN Each client and server needs a NIC rather than a modem Network Interface Card (NIC) In each PC

  9. LANs, MANs, & WANs • WAN • Wide area network • Intercity, international • 9,600 bps to 1 Mbps common to the desktop • Links with higher speed are usually shared (multiplexed) by several desktops • Emerged before LANs, due to high cost of long-distance telephone charges

  10. NetBIOS driver Redirectors Servers WinSock driver Transport Driver Interface Streams Transport Protocols NDIS Interface Streams Network Adapter Card Drivers Network Interface Card Microsoft Layered Network Architecture 7. Application User Mode 6. Presentation Kernel Mode 5. Session 4. Transport 3. Network 2. Data Link LLC MAC 1. Physical

  11. Some basic concepts • NDIS Interface:Network Driver Specification Interface, wraps NIC drivers and allow communication with multiple protocols, binds a NIC to a protocol. • Streams:multiple channels allowing broader bandwidth for data transfer, envelop the protocols. • Transport Driver Interface:allows software drivers (server, redirector, etc) to communicate with protocols. • Redirectors: software in WS that redirect network drives, printers requests to network I/O requests. • Servers: software that allows a device to accept requests from other devices.

  12. Standard protocols • NetBEUI - NetBIOS Extended User Interface, “native” Windows protocol, not routable. • TCP/IP - implemented through WinSock, routable, supports SNMP, DHCP, WINS. • NWLink (IPX/SPX) - used to connect to Novell NetWare, just a protocol, not access. • DLC - Data Link Control, used to connect to IBM mainframes and HP printers directly connected to a network (server).

  13. Data Link Layer Logical Link Control Layer OSI Data Link Layer (Layer 2) Media Access Control (MAC) Layer OSI Physical Layer (Layer 1) 802.3 10Base-T 802.3 10Base-5 802.3 Other Physical Layer 802.5 Physical Layer 4 Mbps 802.5 Physical Layer 16 Mbps Other Physical Layer OSI Data Link Layer is subdivided into two layers Media access control Logical link control

  14. LAN Using Ethernet 10Base-T RJ-45 jacks 10Base-T Hub (Multiport Repeater) 10Base-T UTP Wiring Bundles: 4 Pairs EIA Category 3, 4, or 5 Unshielded Twisted Pair (UTP) Wiring (4-Pair Bundle) PC Network Interface Card RJ-45 Jack NIC

  15. NICs • Network Interface Cards • Implement Physical Layer • Plug and Electrical Signaling • Implements the Data Link Layer (data packaging, access control, etc.) • LLC (802.2) • MAC (802.3 MAC)

  16. Wiring • Unshielded Twisted Pair (UTP) • Twisted several times per foot to reduce interference, T in 10Base- and Unshielded • No protection except for plastic coating • Distance limitation: 100 meters (attenuation, distortion, noise and interference, crosstalk) -- propagation • Categories of UTP Wiring • Category 5: The best. Good for 100 Mbps • Category 3 and 4: lower. May be OK for 100 Mbps • Wiring Plugs: RJ-45 Standard • Similar to home (RJ-11) jacks, but wider

  17. CSMA/CD Media Access Control • CD: Collision Detection • If two stations transmit at once …. • Their signals collide, scrambling one another • Because each sender listens (senses the carrier), both know that there has been a collision • Both stop and wait a random amount of time. 001110 101010 X Collision

  18. Ethernet 10Base-T LAN with Multiple Hubs Hub 2 Hub 3 Hub 1 UTP Wire UTP Wire UTP Wire UTP Wire Station C Hub 4 Daisy chain, no Loops allowed! UTP Wire Station A Station B Station D Maximum distance between farthest Stations is 4 Hubs/5 100 meter segments

  19. Switches With a switch, multiple stations may transmit simultaneously: no congestion as traffic grows. Switch Station C Station A Connection 1 A-C Connection 1 A-C Station D Station B Connection 2 B-D Connection 2 B-D

  20. Wireless LAN Broadcast Signal Antenna Cluster Transceiver Receiving Transceiver Transmitting Hub Controller Transceiver Receiving Wireless LAN

  21. Wireless LAN with Access Points Access Point Industry Standard Coffee Cup Wireless Notebook NIC Antenna (Fan) To Ethernet Switch PC Card Connector

  22. 802.11 Wireless LAN Speeds • 802.11 2 Mbps (rare) 2.4 GHz band (limited in bandwidth) • 802.11b 11 Mbps, 2.4 GHz 3 channels/access point • 802.11a 54 Mbps, 5 GHz (> bandwidth than 2.4 GHz) 11 channels/access point • 802.11g 54 Mbps, 2.4 GHz limited bandwidth

  23. Addresses • Ethernet address (MAC address ) • 48-bit unique addresses hard wired in NICs (280 trillion) • 12 hex numbers, e.g. 00-A0-C9-9F-00-07 • first three identify company, Intel in the example • how to see: IPconfig, or System Information • IP address (number) • 32-bit value, not hard coded (4 billion), assigned manually or by DHCP • four dotted quads, each quad a decimal from 0-255, corresponding to eight bits, e.g. UBMAIL IP address is 198.202.0.25 • to convert open Calculator select View, Scientific, decimal and type dotted quad decimal value, then select binary.

  24. Interneting • Station A wants to send message to station D, but IP number is not in the same subnet -- no can do! • Sends the message to the default IP router -- default gateway • All stations belonging to the same subnet share the first three dotted quads. • 204.52.128.67 and 204.52.128.147 are in the same subnet, while 198.202.0.25 is not.

  25. A,B and C-Class Networks • A-class networks • first 8 bits fixed, from 0-126 (only 127) • very large companies like IBM, BBN, DEC,HP • can assign 3 dotted quads - up to 16 million hosts • B-class networks • first 16 bits fixed, first quad 128-191 and second 0-255 (16,384) • Medium-sized companies like Microsoft, Exxon • can assign 2 dotted quads - up to 65,535 hosts • C-class networks • first 24 bits fixed, first quad 192-223, second and third 0-255 (2,097,152) • can assign 1 dotted quad - up to 253 hosts, 0 is the subnet address., 1 default router address, 255 broadcast address.

  26. Sockets and WinSock • Sockets are the basic TCP requirement • Socket address • IP address of the receiver • Port number of the receiving program (80,21,23) • Type of port TCP or UDP • WinSock is an adaptation of sockets to the PC • it now comes as part of the PC OSs • it is an application programming interface

  27. Internet Host Names • Host names in Windows • HOSTS - a list of IP and names (each machine) • DNS - a server with a common table of IP & names (use with Windows 2000, together with Active Directory) • WINS - Windows Internet Name Server • not DNS compatible (use only with NT/9x) • can resolve IP addresses inside a Windows network • good with dealing with NetBEUI names • FQDN • Fully Qualified Domain Name • name of a host like: machine.org.domain, e.g. ubmail.ubalt.edu, with a DNS assignment to an IP

  28. Setting static IP addresses • Open Control Panel and select Network Connections • Under LAN or High-Speed Internet select local area connection, • right-click and select properties • select Internet Protocol (TCP/IP) and click on properties • fill in IP number, Subnet Mask, Default Gateway and DNS server • click OK, close. • Use ping to test your setup.

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